Conducting Academic Foundations in Scientific Inquiry
In the world of Mechanical and Aerospace Engineering (MAE) at Princeton, a fundamental course called Thermodynamics delves into the intricacies of heat transfer and the relationship between heat and other types of energy. However, this article is not about the theoretical aspects of Thermodynamics but rather an unexpected project that arose from an open-ended assignment.
Enter the PUTT-PUTT Sustainable Bus Project, a brainchild of MAE student Nico Viglucci '19. The project aims to transform a 1998 Thomas-Transit Liner school bus into a sustainable mobile home. A key component of this transformation is the installation of an efficient heating and cooling system.
The HVAC subteam of the PUTT-PUTT project is responsible for designing and building this system. They are focusing on creating a heat pump system for maximum efficiency and practical engineering application. The process of heat pumps explains how comfortable temperatures are maintained in most living spaces, and the PUTT-PUTT team is no exception.
To design heat pumps for sustainable mobile homes, key considerations include compactness, energy efficiency, low-GWP refrigerants, and integration with smart systems. The HVAC subteam is using compact, self-contained packaged heat pump units tailored for mobile homes to optimize space and ease installation.
Maximizing seasonal energy efficiency ratio (SEER) and heating performance is another crucial factor. The team is selecting units with high SEER ratings, such as those with 13+ SEER, and utilizing refrigerants with low global warming potential, like R-454B, to balance performance with environmental impact.
Incorporating reversible heat pump cycles to provide both cooling and heating ensures year-round comfort in diverse climates and reduces reliance on separate systems. The HVAC subteam is also leveraging advanced controls and smart technologies to optimize operation, using AI-driven HVAC systems that adjust temperature settings based on occupancy, weather, and energy pricing.
Integrating demand-flexible operation and load-shifting features allows heat pumps to work flexibly with renewable energy sources or grid needs, increasing overall sustainability and grid compatibility. The team is also considering form factor and installation practicality, using packaged units that include all components in a single cabinet to fit space-limited mobile homes and reduce installation complexity and costs.
Exploring alternative and complementary heat sources, such as geothermal heat pumps using stable ground temperatures, is also on the table where feasible to improve efficiency. However, these are less common in mobile home contexts due to installation complexity and cost.
Prioritizing refrigerant choice and environmental impact is a top priority for the team. They are selecting low-GWP refrigerants to reduce greenhouse gas emissions throughout the product lifecycle.
In summary, mobile home heat pump design for sustainability combines efficient, compact packaged units with smart, flexible controls and environmentally friendly refrigerants, balancing performance, cost, and ease of installation for practical everyday application. This approach supports energy savings, decarbonization goals, and occupant comfort effectively.
The PUTT-PUTT team's innovative approach to sustainable living is a testament to the unexpected opportunities that can arise from open-ended assignments, turning a classroom project into a real-world application with tangible benefits.
[1] Carrier’s SmartComfort PHM4 Mobile Home Packaged Heat Pump: https://www.carrier.com/residential/en/us/products/heating-cooling-systems/heat-pumps/smartcomfort-phm4-mobile-home-packaged-heat-pump/ [2] SEER Ratings and Energy Efficiency: https://www.energystar.gov/products/heating_cooling/air_conditioners/energy_efficiency_and_seer [3] Understanding Heat Pump Cycles: https://www.energystar.gov/products/heating_cooling/heat_pumps/heat_pump_basics [4] AI-Driven HVAC Systems: https://www.schneider-electric.com/en/trends-and-insights/articles/how-ai-is-transforming-hvac/ [5] Low-GWP Refrigerants: https://www.energystar.gov/products/heating_cooling/air_conditioners/environmentally_friendly_air_conditioners/refrigerants
